Three-quarters of U.S. children who died from complications of influenza were not vaccinated before their deaths, according to a study that said 65 percent of adolescent deaths related to the flu from 2010 through 2014 could have been prevented.

The study was released online Monday in the medical journal Pediatrics, noted HealthDay.

The study's findings focused on 358 children and teenagers who died of laboratory-confirmed flu over four seasons. Researchers then compared them with three large groups of children whose flu vaccination rates had been tracked.

"This study highlights the importance of annual influenza vaccination for children, especially those with underlying high-risk medical conditions," said the report authored by the CDC's Dr. Alicia Fry and colleagues, according to NBC News.

"Because of the higher risk of severe complications and influenza-associated death among children with underlying conditions, vaccination is especially important for these children."

The study said just under half of all children were vaccinated for the flu over the same period. The shot reduced the risk of death in children by 65 percent overall, but only 51 percent in high-risk children.

"(The flu shot) reduced the chances of dying of flu by 65 percent but it was not 100 percent," said flu vaccine researcher Dr. John Treanor of the University of Rochester Medical Center. "We recognize that the current vaccine is not perfect. But it is substantially better than not getting vaccinated. The vaccine we have now does work but only if you use it."

The CDC said that since 2010, flu-related hospitalizations among children younger than five years ranged from 7,000 to 26,000 in the United States. The agency said that since 2004-2005, CDC-reported flu-related deaths in children during regular flu seasons have ranged from 37 deaths to 171 deaths.

Three-quarters of U.S. children who died from complications of influenza were not vaccinated before their deaths, according to a study released on Monday that said 65 percent of adolescent deaths related to the flu from 2010 through 2014 could have been prevented.